The Long Life of Death Valley

August 6, 2014

Death Valley is a land of extremes—among the hottest, driest and lowest points on earth. Why would anyone choose to spend spring break there?

“It just sounds very exotic,” says Nicholas Christie-Blick, a geology professor and research scientist at Columbia University’s Lamont-Doherty Earth Observatory. “It’s very far away from their personal experience.”

This past spring, Christie-Blick led his tenth undergraduate fieldtrip to California’s Death Valley National Park. For seven days, a group of freshmen and sophomores followed him up mountains and alluvial fans, through canyons and ancient sea beds, learning about the events that have shaped this part of the Basin and Range Province, a landscape still forming today as the western United States slowly stretches apart. As cracks open in earth’s crust, mountains are uplifted and valleys dropped down. This repeating set of steep mountains and flat, dry valleys, runs from Idaho to northern Mexico.

In Death Valley, among the youngest and most volcanically active parts of the Basin Range, many of the students ticked off several life firsts: first time hunting for fossils and sleeping under the stars, first time walking into the crater of a recent volcanic explosion and cooking enchiladas for a group of 20. The trip has become so popular that Christie-Blick routinely turns students away while many of those who finish the course go on to become earth and environmental science majors. Not a bad record for a fieldtrip once deemed too morbid to attract takers.

University geology departments are full of people who came to the field after a life-changing experience outdoors. For Christie-Blick, it was a fieldtrip to Scotland’s Isle of Arran as a student at Cambridge University. Fascinated by the varied landscape and the stories it held, he abandoned physics. Now a veteran geologist, he tries to recreate that sense of spontaneous exploration and discovery he felt when he was the same age as his students.

To hold their interest he refuses to lecture. It would be easier and quicker to stand at an outcrop and tell the students what they need to know. Instead, he lets them look for themselves and interpret what they see. “Everything in geology is a series of steps,” he says, under a sandstone arch called Natural Bridge. “We can see what it is now but how did it get that way?”

To understand how it got that way, Christie-Blick will walk his students around a mountain to where the orientation of a fault is visible, as he did at Mosaic Canyon. He will urge them to look at grains of sand under their hand lenses, as he did at Calico Hills, near Las Vegas. He will ask them to sketch what they see, as he did at Emigrant Pass. “Their drawings are not necessarily very good—that’s not the point,” he says. “It’s the whole exercise of looking that contributes to their understanding.”

He will often seem unbothered if they miss the point. “Sometimes he seems reluctant to tell them the answer, which is his way of letting the students come to their own conclusions,” said John Templeton, a graduate student at Lamont-Doherty who served as Christie-Blick’s teaching assistant.

The answers don’t particularly matter, Christie-Blick admits. “I want to see how they get to the answer. I want them to come away with an appreciation of how science is done.”

Christie-Blick has spent more than four decades studying past climate and tectonics in the Basin and Range, including as a PhD student at the University of California at Santa Barbara. Still, many questions remain, and Christie-Blick likes to also introduce his students to the frontier of his field. For that reason, he includes a seven-page bibliography referencing all the primary research they discuss.

Standing at Badwater Turtleback, where a gently-sloping fault is exposed on a tall canyon wall, Christie-Blick ticks off the explanations for this geological oddity. Normally, extensional faults like this one should form a steep angle, to overcome friction. Yet, several places in the Basin and Range are sloped at low angles. Is there something we have yet to learn about fault mechanics? Or has a later event like a landslide reoriented the rocks to appear as a low-angle fault?

This is one of the problems that Christie-Blick himself is studying in Death Valley. What geologists learn here, in the Basin and Range, about extensional faulting and the stretching of earth’s crust, may be applied to western Turkey and Greece’s Aegean Islands where similar processes are underway.

At Badwater Turtleback and other outcrops, Christie-Blick offers research ideas, challenging his students to join the debate. At least one has. After a 2008 trip that introduced the mystery of Ubehebe Crater’s age, Perri Sasnett returned to the crater to collect rock samples. With Christie-Blick and her former teaching assistant, Brent Goehring, now a professor at Tulane University, she used surface-exposure dating to date the rocks spewed during Ubehebe’s last explosion. To their surprise, the results showed Ubehebe had exploded as recently as 800 years ago, suggesting that parts of Death Valley may be more volcanically active than previously thought.

Each trip presents its hardships. This year, when both vans got stuck in the sand, the students figured out how to get them out by jacking up the vehicles and sliding rocks under the wheels to provide traction. They braved a sandstorm on their second night camping but no one complained when Christie-Blick sounded the gong to make breakfast. At the last outcrop, on the last day of the trip, the students gave Christie-Blick a standing ovation to the tune of the Columbia fight song: Roar, Lion, Roar! His love of the rocks, it turned out, was contagious.

“He takes first and second year undergraduates with very little earth science education and takes them right up to graduate level questions, observations and interpretations,” said Templeton. “By the end of the week they have come a lot farther than they thought they would, or thought they could, and that’s fun to see.”